Various hybrid powertrain architectures are known for managing the input and output torques of various prime-movers in hybrid vehicles, most commonly internal combustion engines and electric machines. Hybrid powertrain systems are generally characterized by an internal combustion engine and one or more electrical machines which provide motive torque to a vehicle driveline using a transmission device.
One parallel-hybrid powertrain architecture comprises a two-mode, compound-split, electro-mechanical transmission which has an input member for receiving motive torque from a source, e.g. an internal combustion engine, and an output member for delivering motive torque from the transmission, typically to a driveline of a vehicle. First and second electrical machines comprising motor/generators provide motive torque to the transmission and are operatively connected to an energy storage device for interchanging electrical power between the storage device and the first and second motor/generators.
Operation of various components and systems of the hybrid powertrain system and the vehicle typically requires a control system using one or more electronic controllers. The controllers are used to control various aspects of the vehicle. The vehicle system requires ongoing control to meet operator demands for driveability and fuel economy, meet system demands related to the hybrid system, including charging and discharging of energy storage devices, provide accessory capability and demands, and meet mandated requirements for emissions and durability.
A designer deciding upon an architecture for a control system of a hybrid system must balance multiple, competing requirements, including providing sufficient computing power to accomplish various vehicle, powertrain and subsystem management tasks in a timely manner while being cost-effective. Other issues include having a control system which meets quality, reliability and durability targets, is able to comply with electromagnetic interference requirements, and is packagable within the vehicle. When multiple controllers are used, communications between the controllers may be constrained by availability and bandwidth of a local area network. There is also a need to have a control system architecture that has a level of reusability, thus being portable to multiple vehicle platforms and systems with minimal redesign. There is a further need to have a control system which is readily expanded to accommodate new features and capabilities during a system life cycle. There is also a need to have a control system which communicates readily with outside systems, to accomplish such tasks as system calibration, programming, and diagnostics.
Therefore, there is a need for an optimized control system architecture for a hybrid powertrain system which effectively uses on-board computing resources to meet the aforementioned requirements.